Files
hermes-agent/docker/main-wrapper.sh
Ben Barclay 343c54e35b fix(docker): reject unsupported --user <arbitrary-uid> start with clear guidance (#38579)
`docker run --user $(id -u):$(id -g)` was a tini-era trick to make
container-written files match the host user. Under s6-overlay it no longer
works: the bootstrap (UID remap, volume + build-tree chown, config seeding)
needs root, and the baked image dirs (/opt/data, /opt/hermes/.venv, ui-tui,
node_modules) are owned by the hermes build UID (10000). A pinned arbitrary
UID can't write them, so the runtime fails with EACCES on a bind mount or
hard-crashes on a named volume (Docker inits the volume from the image as
10000; the non-root start can't even `cd /opt/data`, and the profile
reconciler dies with PermissionError on gateway_state.json).

Detect that start early in both the cont-init hook (stage2-hook.sh) and the
CMD wrapper (main-wrapper.sh) and fail fast with actionable guidance pointing
at the supported path: root start + HERMES_UID/HERMES_GID (or the PUID/PGID
aliases), which remaps the hermes user and chowns the volume — the same
host-UID-matching outcome --user was used for, without breaking s6.

The guard fires only when the current UID is neither root NOR the hermes UID.
This preserves the supported non-root start from #34648/#34837 (running with
`--user 10000:10000`, i.e. pinned to the hermes UID itself), which is
unaffected — only the arbitrary-UID variant that #34837 never actually made
writable is rejected.

Verified live across five scenarios (built image, bind + named volume):
arbitrary --user on bind -> rejected with guidance, hermes does not run;
arbitrary --user on named volume -> guidance shown, no raw 'can't cd' crash;
--user 10000:10000 -> boots; root + HERMES_UID=4242 remap -> boots, guard not
tripped; default root start -> boots. Pre-fix control reproduces the raw
PermissionError + 'can't cd' crash with no guidance.
2026-06-04 10:51:51 +10:00

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#!/command/with-contenv sh
# shellcheck shell=sh
# /opt/hermes/docker/main-wrapper.sh — wraps the container's CMD with
# the same argument-routing logic the pre-s6 entrypoint.sh used. Runs
# as /init's "main program" (Docker CMD) so it inherits stdin/stdout/
# stderr from the container.
#
# Shebang note: /init scrubs env before invoking CMD, so a plain
# `#!/bin/sh` wrapper sees an empty environ and `ENV HERMES_HOME=/opt/data`
# from the Dockerfile never reaches `hermes`. with-contenv repopulates
# the env from /run/s6/container_environment before exec'ing, which is
# what s6-supervised services use too (see main-hermes/run).
#
# Routing:
# no args → exec `hermes` (the default)
# first arg is an executable → exec it directly (sleep, bash, sh, …)
# first arg is anything else → exec `hermes <args>` (subcommand passthrough)
#
# Drop to hermes via s6-setuidgid, but skip it when already non-root.
set -e
drop() { [ "$(id -u)" = 0 ] && set -- s6-setuidgid hermes "$@"; exec "$@"; }
# --- Reject the unsupported `docker run --user <uid>:<gid>` start ---
# Mirror the guard in stage2-hook.sh (cont-init). This is the surface the
# user actually sees in `docker run` output: when the container is pinned to
# an arbitrary non-root, non-hermes UID, the bootstrap was skipped and the
# baked image dirs (owned by the hermes build UID) are unwritable, so fail
# fast here with actionable guidance rather than crashing on `cd`/EACCES
# further down. See stage2-hook.sh for the full rationale.
cur_uid="$(id -u)"
if [ "$cur_uid" != 0 ] && [ "$cur_uid" != "$(id -u hermes)" ]; then
cat >&2 <<EOF
[hermes] ERROR: container started with --user $cur_uid (an arbitrary, non-hermes UID) — not supported.
To make container-written files match your HOST user, don't use --user.
Start as root (the default) and pass your host UID/GID instead:
docker run -e HERMES_UID=\$(id -u) -e HERMES_GID=\$(id -g) ...
NAS users (Synology / unRAID / UGOS) can use the PUID/PGID aliases:
docker run -e PUID=\$(id -u) -e PGID=\$(id -g) ...
The image remaps the hermes user to that UID/GID at boot and chowns the data
volume, so files land owned by your host user — the same outcome --user gave,
without breaking the s6 supervision tree.
EOF
exit 1
fi
# HOME comes through with-contenv as /root (the /init context). Override
# to the hermes user's home before dropping privileges so libraries that
# resolve paths via $HOME (e.g. discord lockfile under XDG_STATE_HOME)
# don't try to write to /root.
export HOME=/opt/data
# Save the Docker -w (or default) working directory before init
# scripts cd to /opt/data, so the container starts in the
# directory the user requested.
_hermes_orig_cwd="${HERMES_ORIG_CWD:-$PWD}"
cd /opt/data
# shellcheck disable=SC1091
. /opt/hermes/.venv/bin/activate
# Restore the original working directory before handing off to
# the user's command so `hermes chat` starts in the Docker -w
# directory, not /opt/data.
cd "$_hermes_orig_cwd"
if [ $# -eq 0 ]; then
drop hermes
fi
if command -v "$1" >/dev/null 2>&1; then
# Bare executable — pass through directly.
drop "$@"
fi
# Hermes subcommand pass-through.
drop hermes "$@"